Complete question is:
The brand manager for a brand of toothpaste must plan a campaign designed to increase brand recognition. He wants to first determine the percentage of adults who have heard of the brand. How many adults must he survey in order to be 80% confident that his estimate is within six percentage points of the true populationpercentage?
Complete parts (a) through (c) below.
1) Assume that nothing is known about the percentage of adults who have heard of the brand.
a.n=_________(Round up to the nearest integer.)
2) Assume that a recent survey suggests that about 85% of adults have heard of the brand.
b.n=_________(Round up to the nearest integer.)
3) Given that the required sample size is relatively small, could he simply survey the adults at the nearest college?
A.No, a sample of students at the nearest college is a stratified sample, not a simple random sample, so it is very possible that the results would not be representative of the population of adults.
B.No, a sample of students at the nearest college is a clustersample, not a simple random sample, so it is very possible that the results would not be representative of the population of adults.
C.Yes, a sample of students at the nearest college is a simple random sample, so the results should be representative of the population of adults.
D.No, a sample of students at the nearest college is a convenience sample, not a simple random sample, so it is very possible that the results would not be representative of the population of adults.
Answer:
1) 114
2) 58
3) Option D
Step-by-step explanation:
From tables, the critical value of a confidence interval of 80% is 1.282.
1) I have attached the explanation
2) I have attached the explanation
3) When our sample is nearby, we simply make use of a convenience sample.
Now, convenience samples are biased. Therefore it is not a good sampling methodology.
Therefore, we can say that:
No, we should not just simply survey the adults of the nearest college due to the fact that it is a convenience sample.
The option that corresponds to the conclusion is option D.
